Verification of Degradation of n-Alkanes in Diesel Oil by Pseudomonas aeruginosa Strain WatG in Soil Microcosms

Abstract

Degradation of n-alkanes in diesel oil by Pseudomonas aeruginosa strain WatG (WatG) was verified in soil microcosms. The total petroleum hydrocarbon (TPH) degradation level in two bioaugmentation samples was 51% and 46% for 1 week in unsterilized and sterilized soil microcosms, respectively. The TPH degradation in the biostimulation was of control level (15%). The TPH degradation in aeration-limited samples was clearly reduced when compared with that in aeration-unlimited ones under both sterilized and unsterilized conditions. Addition of WatG into soil microcosms was accompanied by dirhamnolipid production only in the presence of diesel oil. These findings suggest that degradation of n-alkanes in diesel oil in soil microcosms would be facilitated by bioaugmentation of WatG, with production of dirhamnolipid, and also by participation of biostimulated indigenous soil bacteria

Isolation and characterization of bacteria from soil contaminated with diesel oil and the possible use of these in autochthonous bioaugmentation

“…One possibility is that the cooperation may be mediated by rhamnolipids produced by P. aeruginosa strain WatG, which has an ability to secrete such substances under liquid and soil cultivation conditions (Ueno et al 2006a). The observation that isolate N grew in liquid LB and soil extract media, but not in MSM, containing diesel oil (data not shown) suggests that diesel oil becomes available because of emulsification by the biosurfactant rhamnolipids secreted by P. aeruginosa strain WatG.…”

“…Bacteria were precultivated in LB medium at 20°C overnight and inoculated to the above media to a final concentration of 0.1 at OD 600 (Ueno et al 2006a;2006b). …”

“…Soil microcosms supplemented with a culture of P. aeruginosa strain WatG plus LB medium, and also with LB medium alone were designated P. aeruginosa strain WatG-bioaugmented (WatG-BA) and LB-biostimulated (LB-BS) soil microcosms, respectively (Ueno et al 2006a). …”

“…Previously, we investigated the microbial community structure of diesel-oil-contaminated local paddy soil microcosms that had been biostimulated with Luria-Bertani medium (LB-BS) or bioaugmented with a petroleum-degrading bacterium, Pseudomonas aeruginosa strain WatG (WatG-BA; Wongsa et al 2004;Ueno et al 2006a), by using denaturing gradient gel electrophoresis (DGGE) and monitoring diesel oil degradation (see Fig. 1A; Ueno et al 2006b).…”

Aislamiento de bacterias potencialmente degradadoras de petróleo en hábitats de ecosistemas costeros en la Bahía de Cartagena, Colombia

“…Estos, tienen una ventaja amplia frente a las bacterias Gram positivas, debido a que son considerados importantes degradadores de hidrocarburos por la presencia de lipopolisacaridos en su membrana, que facilitan la formación y estabilización de emulsiones de hidrocarburos en sistemas acuosos y contribuyen al incremento en la superficie de ataque del contaminante (40). Pérez et al, 2008 (24), sustenta que las comunidades microbianas en áreas contaminadas son dominadas por los organismos capaces de utilizar o sobrevivir a compuestos tóxicos, como los ambientes contaminados con hidrocarburos, tal es el caso del género Pseudomona.…”